Fig. 2
Structural characterization of CaMnt1 protein. (A) Far-UV CD spectra of CaMnt1 at pH 5.0, 7.0 and 9.5 at 25 °C. The CaMnt1 protein (0.11 mg/mL) was solubilized in 5 mM sodium citrate (pH 5.0), 5 mM Tris HCl (pH 7.0) and 5 mM glycine (pH 9.5). (B) Thermal denaturation profiles of MNT1. Unfolding curves of MNT1 (0.11 mg/mL) were monitored by changes of [θ]208 nm from 25 to 95 °C. The protein was solubilized in 5 mM sodium citrate pH 5.0 (black), 5 mM Tris HCl pH 7.0 (red line), and 5 mM glycine 9.5 (blue line). The arrows indicate a Tm of 54.5 °C at pH 7.0 and a Tm of 43.3 °C at pH 9.5. (C) Fluorescence emission of CaMnt1 as function of pH. Emission spectra changes were measured at different pH’s using 10 mM sodium citrate (pH 4.0‒5.5), 20 mM Tris HCl (pH 6.0‒9.0) and glycine (pH 9.5) with a range difference of 0.5. The emission bands centered at 332 nm displayed maximum fluorescence intensity at pH 7.0 (solid red line)